The Art and Science of Low Carbohydrate Performance

True science discussed. Amazing the misquotes that are in the nutritional literature when people bash keto and low carb diets.

Well written, highly credentialed and experienced in subject matter authors, well documented, and thorough coverage of the topic. They basically make the case that high carb diets and carbo-loading for endurance athletes is outdated. And they make the case that the exact opposite is what yields the best results: high fat, low carb. One reason that high carb might still be so prevalent is that it takes 2-3 weeks for your body to adapt to a low carb, high fat diet. Results don't come until after you are fully "keto-adapted." Most athletes are apparently not patient enough to go through this frustrating adaptation process.Ketones are the breakdown products of fats that your brain can burn for energy. But, if lots of sugar from carbs are present in the blood, then the brain will not burn ketones, only sugar. It takes two weeks of consistently maintained target blood levels of ketones in order for the brain to produce enough ketone pumps to allow enough into the brain cells for normal energy production. The main inhibiting factor for high blood ketone levels is insulin. The only way to keep insulin levels low enough to allow ketones to rise high enough is to stay away from high amounts of dietary sugars and carbs.Along with low insulin levels comes the transition allowing muscles to burn fatty acids instead of glucose. Since body stores of glucose are at best 2 hours worth of energy, and fat stores are essentially unlimited, we see that muscles trained to burn fat instead of glucose as their primary fuel is optimal for endurance sports. And, not only will your muscles never run out of fuel (even if you don't refuel during your race), but neither will your brain. In fact, the worst part about "hitting the wall" due to low glycoge/glucose stores during a race is mental confusion due to low blood glucose.In a study of several non-athletes who were keto-adapted, researchers injected insulin into the subjects until blood glucose levels fell below 30 (normal is 70-120). At this low level, not only did the subjects not fall into a coma, but they didn't have any symptoms of low blood sugar! This is because their brains were burning fat (ketones) for energy, not sugar, making the low glucose levels irrelevant to proper brain function!Obviously, there are non-athletic implications for a low carb diet: natural diabetes control, weight loss (targeting fat loss), and preventing symptoms of low blood sugar (hypoglycemia). It turns out that about 70% of people with seizures are cured by a keto-genic low carb diet.The coolest part of the book is biofeedback available with an inexpensive "ketone" testing machine similar to a diabetic blood sugar testing machine that allows you to know in black and white whether your diet and exercise routine is working or not. If you aren't getting the results you were promised, but your blood levels of ketones are too low, then you know it's because you are doing something wrong. You can test your blood after eating certain foods to get immediate feedback on that food's impact on your body as far as ketones (and thus indirectly insulin) are concerned.The nova max ketone tester is the one I use because its test strips are about half the cost of the other brand. You can find and purchase these on amazon as well.Now that I am keto-adapted for a few weeks now, I have noticed a few differences in my running workouts. 1) My energy is much more stable throughout the workout, 2) I seem to get less dehydrated during workouts (this is likely due to the fact that burning fat uses less water than does burning sugar), 3) I don't seem to have to breath as hard (this might be due to the fact that burning fat gives off 25% less CO2 than burning sugar), and 4) The runners high is less obvious at the end of my workout (upon reflection, I think that this is because I seem to have a low level of runners high all the time now, not just after running).One downside is that I seem to be thirstier between workouts. In the book they say that when ketoadapted, the body shifts from conserving sodium and peeing out potassium, to conserving potassium and peeing out sodium. This may explain why I am thirstier since if I am peeing out my salt, I can't retain as much water, thus am more dehydrated easier. It is interesting that even though I feel more dehydrated between workouts, my mouth is much more moist during workouts. Maybe this is because I'm not breathing as hard during the workout?

I recently completed a 545mile bike ride over 7 days and gained over 10lbs (not all muscle), and it was after that that I realized I needed to make some serious dietary changes. I started working with a nutritionist, and have started a version of low carb, but never with the expectation of cutting carbs out. I wasn’t sure how to fuel on rides anymore when I was eating mostly vegetables and protein. My nutritionist recommended this book as a starting point.I found this to be a difficult, but interesting read. Like the authors said, it did become acronym soup after a couple chapters, which made for difficulty in understanding the science. I found I kept flipping to the glossary, and then back to where the term was first introduced to remind myself of what it was. I’m still not sure I grasped all of the science, but I believe I have the main points.I’m intrigued by the concepts, but not sure it fully gave me the tools I need to actually make the shift to low carb. For one, most of their recommended food substitutes included a lot of dairy, which I cannot eat, so there I would need more guidance. It also didn’t answer the basics questions I had about, how an athlete would fuel when on a long bike ride or run. The book simply mentions you can go longer without bonking, etc. There were some product recommendations that I will be looking into more.Overall, there’s not a lot of info out there, so I would recommend this book as a good, science backed, place to start.

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This is the first and possibly still only book that talks in depth about why a very low carb ketogenic diet may not just be useful for weight loss, insulin-resistance, metabolic syndrome, heart disease, epilepsy and autoimmune diseases but also to significantly improve athletic performance. The authors have many years of research experience in the field of low carb nutrition and had published another outstanding book, "The Art and Science of Low Carbohydrate Living" last year which focused on the details of doing low carb eating the right way by avoiding the many possible pitfalls.This new book is written for athletes who want to improve their performance, but also for people who want to be athletes and never could be because their body would not cooperate on a higher carb diet.The authors explain in detail how on a higher carb diet the body is dependent on glucose for most of its functions including muscle functions and brain function.Glucose can only be stored in our body in a fairly limited amount, somewhere around 2000 calories. When this supply is close to being exhausted we need to refuel with carbohydrates to keep functioning or we will "hit the wall" as endurance athletes call it, meaning our brain and muscles are running out of fuel. When eating a high carbohydrate diet our body can not quickly switch from fueling with carbohydrate to fueling with fat, even though even a slim person has 40,000 calories of energy on their body at all times from fat.This fat can only be accessed to fuel the muscles and the brain for most of their energy needs if the body is used to using it. Fat is converted to ketones which can fuel the muscles and the brain for most of their energy needs in a keto-adapted person.For keto-adaptation to happen carbohydrate intake has to be drastically reduced, usually at least down to 50 grams/day, in many people to under 20 grams/day at least initially. The reason is that higher carb levels than this will lead to more insulin production and insulin inhibits release and use of fat from our fat storage cells. The graphics in the book show that with even moderate carbohydrate intake (of any form) there is too much insulin for the body to be able to access any significant amount of fat as fuel.Once carb levels are lowered enough the body will start producing ketones from fat and from that point on it takes a few weeks for our body to make all the necessary changes to become fully keto-adapted. The whole process typically takes about 6 weeks, which is why many benefits of a low carbohydrate diet are only optimized after this period. Some improvements, like a lack of hunger and a reduction in body fat, can be seen much earlier, often after just a few days.Once the body is fully keto-adapted something amazing happens:Fat use during exercise increases tremendously with moderate exercise for both endurance exercise and resistance training. In a study of high-level cyclists who had been keto-adpated for 4 weeks the average fat oxidation per hour at about 65% VO2max was about 90 grams/hour.So far I have just summarized the first three chapters. The rest of the book talks about implementing the diet, macronutrient levels, faster recovery rates on ketogenic diets and fluid and mineral management.Just to make sure nobody who buys this book is going to be disappointed: The diet itself is not very different from what you can find in the original Atkins diet: low carb and high fat although there is some additional info here as well. The main benefit I get from this book is to understand how to optimize a low-carb diet to get far superior results from the time I spend exercising.I am planning to measure this by recording my body weight, body fat percentage vs. lean muscle mass and by recording improvements in my running and resistance training over the next 3 months.This book gives enough detail to helpful for serious athletes but is written in a way that anyone who wants to live a healthy lifestyle can understand it.